Disuse osteoporosis is a loss of bone density associated with immobilization and is a common sequelae of spinal cord injured (SCI) patients. The aims of this study are: 1) to determine the bone mineral density in a group of SCI patients who are less than 4 months post injury and 2) to determine what bone mineral density changes occur in a group of SCI patients enrolled in a Functional Electrical Stimulation (FES) walking program.